Ice maker

ABSTRACT

An automatic icemaker in which a flexible ice tray is twisted to loosen the ice cubes by unidirectional rotation of one end of the tray while rotation of the opposite end of the tray is temporarily restrained and a reverse twist force is imparted to the tray by relatively accelerating the other end of the tray before the tray is returned to its normal upright position.

United States Patent Lawrence E. Snow Greenville, Mich.

Jan. 13, 1969 May 25, 1971 White Comolidated Industries, Inc.Greenville. Mich.

Inventor Appl. No. Filed Patented Assignee ICE MAKER 1 Claim, 4 DrawingFigs.

US. Cl 62/353, 62/72 Int. Cl F 25c 1/10 Field of Search 62/72, 353

[5 6] References Cited UNITED STATES PATENTS 3,382,682 5/1968 Frohbieter62/72 3,056,271 10/1962 De Turk 62/353 3,308,631 3/1967 Kniffin 62/72XPrimary ExaminerWilliam E. Wayner Attorney-Strauch, Nolan, Neale, Nies &Kuiz ABSTRACT: An automatic icemaker in which a flexible ice tray istwisted to loosen the ice cubes by unidirectional rotation of one end ofthe tray while rotation of the opposite end of the tray is temporarilyrestrained and a reverse twist force is imparted to the tray byrelatively accelerating the other end of the tray before the tray isreturned to its normal upright posit1on..

Patented May 25, 1971 7 3,580,009

' 5' 4 INVENTOR.

LAWRENCE E. SNOW ICE MAKER Recently automatic icemakers particularlythose for use in domestic refrigerators have become increasinglypopular. Most, if not all, of these units comprise a single flexible icetray having a number of molds or pockets which are automatically filledwith water which is then frozen. A sensing device or timer then actuatesthe drive mechanism, which is effective to loosen the ice blocks and theinvert or tilt the tray to deposit the iceblocks in a storage bin.,Thetray is then returned to its upright position and the cycle is repeated.

Generally the ice trays are made of plastic material which possesses thenecessary flexibility to permit the repeated substantial flexing andtwisting of the tray required to loosen the ice cubes. While suchmaterials have a high degree of resiliency, nevertheless, after repeatedcycling particularly in a very low temperature environment, the trayrequires a permanent set in slightly twisted form. Prior proposals toovercome this disadvantage have taken two primary forms. In the firstthe tray is released from its twisted position with a snap action. Anexample of this type of construction is disclosed in US. Pat. No.3,056,271. It has been found, however, that this expedient decreases butby no means eliminates the permanent set taken by the tray.

It has also been proposed to restore its tray to its original shape bypositively reversely twisting the trayby reversing the direction ofrotation of the driven end of the tray while the remote end of the trayis held against rotation by a mechanical stop. While-this type ofconstruction, an example of which is disclosed in US. Pat. No.3,217,510, is effective in eliminating the distortion of the tray,nevertheless, it requires a complicated and expensive drive systemnecessitating the use of gears and cams which are subject to malfunctionand wear. Alternately this type of reverse twist action may be effectedby providing a bidirectional drive for one end of the tray. This againrequires a reversible motor and an associated control circuit which isunduly complex and expensive.

SUMMARY OF THE INVENTION In view of the foregoing background it is theprincipal purpose and object of the present invention to provideimproved icemakers of the typein which a flexible ice tray is twisted torelease the iceblocks and improved simplified low cost and yet ruggedand reliable means for preventing the attainment of permanent set in thetray.

In accordance with the present invention this and other objects areobtained by the provision of a tray drive system in which one end of thetray is rotated unidirectionally at uniform speed through 360 from anormal upright position through an inverted position in which theiceblocks are loosened and delivered to a storage bin, the tray thenbeing returned to its upright position. As the tray approaches orreaches its inverted position it is twisted in one direction about itslongitudinal axis to loosen the iceblocks. Subsequently in the cycle theremote or nondriven end of the tray is accelerated with respect to thedriven end of the tray to impart a reverse twist force to the tray torestore it to its original shape. The acceleration of the remote end ofthe tray is effected by a spring which also serves to retain the remoteend of the tray securely in its supporting structure.

The present invention is particularly adapted for use with associatedstructure such as that disclosed in copending application Ser. No.790,654 filed on even date herewith for lcemaker and owned by applicantsassignee.

Additional objects and advantages will become apparent as thedescription proceeds in connection with the accompanying drawings.

THE DRAWINGS FIG. 1 is a perspective view of a complete automaticicemaker incorporating the subject matter of the present invention;

FIG. 2 is a top plan view of the tray and associated mechanism; and

FIGS. 3 and 4 are enlarged fragmentary sections taken along lines 3-3and 4-4 of FIG. 2.

DESCRIPTION OF PREFERRED EMBODIMENT For present purposes the inventionwill be disclosed as applied to an icemaker of the type disclosed in theaforesaid copending application to which reference may be had fordetails of construction.

In general the icemaker comprises a U-shaped rigid metal frame 20adapted to be mounted in the freezer compartment of a refrigerator. Theframe assembly comprises a base section 22 and sidewalls 24 and 26, thefree ends of which are secured to a housing 28 containing aunidirectional drive motor and associated control mechanism which may beof conventional construction.

The output shaft 30 of the drive motor is drivingly connected to afitting 32 carried by one end of an elongated plastic ice tray 34provided with the usual series of molds or pockets 36 in which the iceblocks are formed. The tray 34 is preferably formed from a flexibleplastic such as polypropylene, which is relatively flexible and capableof being subjected to repeated twisting actions about its longitudinalaxis without deterioration.

At its opposite end the tray is provided with a rigid plastic fitting38. Formed integrally with the fitting 38 is a boss having a generallycylindrical section 40, an enlarged annular shoulder 42, and a reducedcylindrical extension 44, all of which are formed coaxially of the motordrive shaft 30. The reduced boss extension 44 is rotatably received in athrough bore 46 in a bearing 48 having a peripheral groove 50 in whichthe portion of the sheet metal base 22 forming the reduced upper portionof a keyhole opening 52 is received.

The parts thus far described may be assembled by first installing thebearing 48 in the enlarged portion of the keyhole opening 52, moving itupwardly to the position shown, and sliding the driven end of the trayonto the shaft 30. The tray is then displaced to the right as viewed inFIG. 2 to dispose the reduced boss extension 44 within the bearing 48.

The parts are held in assembled relation by a wire spring 54 theoppositeends of which are hooked over the upper edges of the frame base 22, theposition of the spring being determined by a recess 56 which receivesone end of the spring. The spring is held away from the surface of theframe base 22 by a pair of indentations 58 and 60 struck inwardly fromthe frame base 22. The main body portion of the spring is thus disposedinwardly of the shoulder 42 and in engagement with the larger bosssection 40. It is to be particularly noted that the boss section 40 isprovided with a flat 62 of substantial length. When the tray 34 isdisposed in its upright position as shown in FIGS. 1 and 2, the flat 62is disposedat an angle of approximately 5 with respect to thehorizontal. The spring 54 is so constructed that it is at all timesdisplaced from its free or relaxed position shown in dotted lines inFIG. 3 so that it exerts a substantial upward force against the bosssection 40. This force is increased as the tray is rotated away from itsupright position and the spring engages the cylindrical surface of theboss portron.

The operation of the icemaker will now be described, assuming that thetray has been filled with water and that the individual iceblocks havebeen frozen. A sensor, which may be of conventional construction, thenactivates the drive motor which rotates the tray in a clockwisedirection as viewed in FIG. 3. The spring 54 is immediately deflecteddownwardly by the cylindrical surface of the boss portion 40. Therotation of the tray is continued until it is substantially inverted atwhich time a stop surface 64 on the fitting 38 contacts anabutmentsurface 66 formed on one end of a stop bar 68 slidably carried by theframe member 26.

The rotation of the driven end of the tray continues while the rotationof the remote end of the tray is arrested imparting a substantial, forexample, 30 twist which is sulficient to loosen the iceblocks which thenfall into a storage receptacle 70 removably mounted on the lower edgesof the side frame members 24 and 26. ln the continued rotation of thedriven end of the tray a cam surface 72, formed on the fitting 32,engages a cam surface 74 formed on the slide bar 68 which is thendisplaced to the left to bring the abutment surface 66 out ofregistration with the stop surface on the fitting 38. While the traythen tends to resume its original shape it has been found that underrepeated flexing, particularly low temperature, the tray tends to take apermanent set in partially twisted form.

This tendency is eliminated by the spring 54 and the associatedmechanism as follows. After approximately 325 of rotation the end 62a ofthe flat 62 contacts the spring 54. lmmediately after this occurs, thespring 62 tends to restore the adjacent end of the tray to its fullyupright position. Since the driven end of the tray is rotated atconstant speed the remote end of the tray is effectively accelerated,imparting a twist restore the tray to its original shape withoutimposing any appreciable friction loads on the cylindrical portion ofthe boss 40.

Thus the foregoing objects of the invention have been achieved by theprovision of a mechanically uncomplicated arrangement for restoring theice tray to its original shape, the mechanism also being utilized tofacilitate assembly or disassembly of the ice tray and support structureand to hold the parts in proper relation during all phases of operation.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is therefore to be considered in all respects as illustrativeand not restrictive, the scope of the invention being indicated by theappended claims rather than by the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent It isclaimed:

1. An automatic ice maker comprising an ice tray mounted in supportstructure for rotation about a predetermined axis, unidirectional drivemeans connected to one end of said tray for rotating said tray aboutsaid axis in one direction from an upright position through an invertedposition and then to said upright position, means for twisting said trayin one direction about said axis during a portion of said rotation, apivot projecting from said remote end of said tray,said pivot having afirst portion rotatable in said support structure, said pivot having asecond portion provided with a cylindrical surface interrupted by a flatsurface and a spring engageable sequentially with said cylindricalsurface and said flat surface, said spring being effective, when engagedwith said flat surface, to drive said remote end of said tray in adirection to twist said trayin the opposite direction about said axis.

1. An automatic ice maker comprising an ice tray mounted in supportstructure for rotation about a predetermined axis, unidirectional drivemeans connected to one end of said tray for rotating said tray aboutsaid axis in one direction from an upright position through an invertedposition and then to said upright position, means for twisting said trayin one direction about said axis during a portion of said rotation, apivot projecting from said remote end of said tray, said pivot having afirst portion rotatable in said support structure, said pivot having asecond portion provided with a cylindrical surface interrupted by a flatsurface and a spring engageable sequentially with said cylindricalsurface and said flat surface, said spring being effective, when engagedwith said flat surface, to drive said remote end of said tray in adirection to twist said tray in the opposite direction about said axis.